Sample Size Considerations in Prevention Research Applications of Multilevel Modeling and Structural Equation Modeling

When the goal of prevention research is to capture in statistical models some measure of the dynamic complexity in structures and processes implicated in problem behavior and its prevention, approaches such as multilevel modeling (MLM) and structural equation modeling (SEM) are indicated. Yet the assumptions that must be satisfied if these approaches are to be used responsibly raise concerns regarding their use in prevention research involving smaller samples. In this manuscript we discuss in nontechnical terms the role of sample size in MLM and SEM and present findings from the latest simulation work on the performance of each approach at sample sizes typical of prevention research. For each statistical approach, we draw from extant simulation studies to establish lower bounds for sample size (e.g., MLM can be applied with as few as 10 groups comprising 10 members with normally distributed data, restricted maximum likelihood estimation, and a focus on fixed effects; sample sizes as small as N = 50 can produce reliable SEM results with normally distributed data and at least three reliable indicators per factor) and suggest strategies for making the best use of the modeling approach when N is near the lower bound

Maximizing the Yield of Small Samples in Prevention Research: A Review of General Strategies and Best Practices

The goal of this manuscript is describe strategies for maximizing the yield of data from small samples in prevention research. We begin by discussing what “small” means as a description of sample size in prevention research. We then present a series of practical strategies for getting the most out of data when sample size is small and constrained. Our focus is the prototypic between-group test for intervention effects; however, we touch on the circumstance in which intervention effects are qualified by one or more moderators. We conclude by highlighting the potential usefulness of graphical methods when sample size is too small for inferential statistical methods

Grit as Predictor of Entrepreneurship and Self-Employment in Spain

Extending the growing literature on the role of grit in different life domains, this research explores the relationship between grit and involvement in entrepreneurship. The research highlights the role of personal income and satisfaction with one’s current financial situation as moderators of the relationship between grit and entrepreneurial behavior. Using a large representative sample of Spanish young adults and controlling for a number of potential confounding variables, we find that grit is modestly negatively related to the probability of involvement in entrepreneurship. As predicted, however, this relationship is qualified by both income and satisfaction with current financial situation, though in opposite directions and more weakly for satisfaction with financial status. Gritty individuals with higher levels of income are more prone to become entrepreneurs than gritty individuals with lower levels of income. Gritty individuals with lower levels of satisfaction with their financial situation are more likely to set up a business or become self-employed

Self-focused attention in anorexia nervosa: Self-Focused Attention in Anorexia Nervosa

The clinical presentation of anorexia nervosa (AN) is characterized by preoccupation with body experience, intrusive concerns regarding shape, and pathological fears of weight gain. These symptoms are suggestive of unrelenting self-focused attention. No research to date has characterized self-focused attention (SFA) in AN nor examined neurocognitive features that may facilitate an excessive, rigid, or sustained focus on one’s appearance

Second language anxiety among Latino American immigrants in Australia

Research into second language anxiety (SLA) has largely focused on second language learners rather than immigrants. However, living in an environment where the target language (TL) is the language of everyday communication may constitute a significant source of anxiety that generalizes beyond the language classroom [Pappamihiel, N. E. 2001. “Moving from the ESL Classroom into the Mainstream: An Investigation of English Language Anxiety in Mexican Girls.” Bilingual Research Journal 25: 31–39. doi:10.1080/15235882.2001.10162783; Rose, Glenda. 2008. “Language Acculturation Anxiety in Spanish Apeaking Adult Immigrants Learning English in the United States.” PhD diss., University of Texas. Available from ProQuest Dissertations and Theses database (UMI No. 3315370); Woodrow, L. 2006. “Anxiety and Speaking English as a Second Language.” RELC Journal 37: 308–328. doi:10.1177/0033688206071315]. This study explored SLA across different social contexts in a sample of 190 adult immigrants from Latin America to Australia who spoke Spanish as their first language (L1) and English as their second language (L2). The aims were to (a) investigate the presence and severity of SLA among L2 long-term immigrants, and (b) examine sources of individual differences in SLA. Results indicated that SLA exists among L2 immigrants at moderate, high and very high levels, and that levels of anxiety vary significantly across social contexts. Self perceived L2 proficiency was found to be the strongest predictor of SLA followed by extroversion and age, with higher scores on all three variables associated with lower SLA. Gender, education level, duration of residency in Australia, and emotional stability did not predict SLA in any of the contexts. These findings suggest that SLA is a significant problem for adult immigrants, permeating most aspects of their everyday lives. Practical implications and recommendations for future research are discussed

Sensation seeking and its relationship with psychopathic traits, impulsivity and aggression: a validation of the Dutch Brief Sensation Seeking Scale (BSSS)

Sensation seeking is a personality trait that manifests as a preference for change, variety and novelty. Sensation seeking has been positively associated with different externalising behaviours. However, its associations with psychopathic traits, impulsivity and aggression are unclear. These associations were examined via the psychometric properties of the Dutch version of the Brief Sensation Seeking Scale (BSSS) using individuals from the general population and forensic patients. The results show that the BSSS has good psychometric properties, including test-retest reliability and a four-factor structure. Additionally, the results support associations between sensation seeking and psychopathic traits, impulsivity and total scores of aggression but revealed no specific associations with different types of aggression (e.g. proactive and reactive). The Dutch BSSS is a valuable tool for assessing sensation seeking in both the general population and forensic patients. Future research should further examine its utility and explore the role of sensation seeking in antisocial conduct

Initial Validation of a Self-Report Measure of the Extent of and Reasons for Medication Nonadherence

Self-report measures of medication nonadherence confound the extent of and reasons for medication nonadherence. Each construct is assessed with a different type of psychometric model, which dictates how to establish reliability and validity

Characterizing weekly self-reported antihypertensive medication nonadherence across repeated occasions

BackgroundLittle is known about weekly variability in medication nonadherence both between and within persons.PurposeTo characterize medication nonadherence across repeated, closely spaced occasions.MethodsThis prospective cohort study comprised four unannounced telephone assessment occasions, each separated by approximately 2 weeks. On each occasion, adult outpatients taking at least a single antihypertensive medication completed a measure of extent of, and reasons for, nonadherence.ResultsTwo hundred and sixty-one participants completed 871 (83%) of 1,044 occasions. Nonadherence was reported on 152 (17.5%) of 871 occasions by 93 (36%) of 261 participants. The most commonly endorsed reasons for nonadherence were forgetting (39.5%), being busy (23.7%), and traveling (19.7%). Among 219 participants completing at least three occasions, 50% of the variability in extent of nonadherence was a result of within-person fluctuations, and 50% was a result of between-person differences.ConclusionInterventions to reduce nonadherence should be informed by variability in the extent of nonadherence and specific reasons for nonadherence

Associations between message features and subjective evaluations of the sensation value of antidrug public service announcements.

In 1998, the U.S. Congress stepped up the nation's focus on drug and alcohol abuse by allocating $1 billion to the Office of National Drug Control Policy for mass media-based prevention campaigns and evaluations. We now know some of the key elements of effective media-based antidrug campaigns, including effec

Crop Updates 2009 - Genetically Modified Crops, Nutrition, Soils, & Others

This session covers fifteen papers from different authors: 1. Performance of Canola Breeders Roundup Ready® canola hybrid CHYB-166 in 2008, Wallace Cowling, Canola Breeders Western Australia Pty Ltd 2. The implications of GM glyphosate resistant lupin, Art Diggle, Caroline Peek, Frank D’Emden, Fiona Evans, Bob French, Rob Grima, Sam Harburg, Abul Hashem,, John Holmes, Jeremy Lemon, Peter Newman, Janet Paterson, Steve Penny,Department of Agriculture and Food, Peter Portmann, Agriconnect 3. Nufarm Roundup Ready® Canola Systems Trials— 2008 Mark Slatter, Research and Development Officer, Victoria, Nufarm (0438 064 845) Angus MacLennan, Business Development Manager, New South Wales, Nufarm (0408 358 024) Cooperators: Monsanto, Nuseed, Pacific Seeds, Pioneer Seeds 4. Roundup Ready® canola—2008 Limited Commercial Release. Getting the system right, Andrew Wells and Mark Slatter, Nufarm Australia Limited (Reprint from 2008 GRDC Cropping Updates with Introductory note) NUTRITION 5. Fertilising in a changing price environment, Bill Bowden1, Wayne Pluske2 and Jeremy Lemon1, 1Department of Agriculture and Food, 2Back Paddock Company 6. Making better fertiliser for Western Australian cropping systems, Wen Chen1 2, Geoff Anderson1, Ross Brennan1and Richard Bell2 1Department of Agriculture and Food, 2School of Environmental Science, Murdoch University 7. The nitrogen fertiliser replacement value of biosolids from wastewater treatment, Hannah Rigby1, Deborah Pritchard1, David Collins1, Katrina Walton2, David Allen2 and Nancy Penney31School of Agriculture and Environment,Curtin University of Technology, Muresk Campus, 2Chemistry Centre of Western Australia 3Water Corporation of Western Australia 8. Fertilising to soil type (usually) pays, Michael Robertson, Bill Bowden and Roger Lawes, CSIRO, Floreat and Department of Agriculture and Food SOILS 9. Management of subsoil acidity and compaction using a combination of lime, deep ripping and controlled traffic, Stephen Davies, Chris Gazey, Breanne Best and David Gartner, Department of Agriculture and Food 10. Optimising gypsum applications through remote sensing and Variable Rate Technology, Frank D’Emden, Department of Agriculture and Food and Quenten Knight,Precision Agronomics Australia 11. Case study of a 17 year agricultural lime trial, Chris Gazey1, Joel Andrew2and Ryan Pearce3 1Department of Agriculture and Food; 2Precision SoilTech; 3ConsultAg 12. Soil organic carbon in WA agricultural soils, FC Hoyle and A Bennett, Department of Agriculture and Food OTHER 13. Is the no-till revolution complete in WA? Frank D’Emden1, Rick Llewellyn2 and Ken Flower3 1Department of Agriculture and Food, 2CSIRO Sustainable Ecosystems, 3University of Western Australia 14. Progression Planning (The Concept), Julian Krieg and Owen Catto, Wheatbelt Men’s Health 15. Is the Department of Agriculture and Food still a primary source of cropping information? Cindy Parsons, Department of Agriculture and Foo